UNIVERSITY    OF    CALIFORNIA 

COLLEGE     OF     AGRICULTURE 

AGRICULTURAL    EXPERIMENT    STATION 

BERKELEY,    CALIFORNIA 

CIRCULAR  293 

June,  1925 

THE  BASIS  OF  GRAPE  STANDARDIZATION 

FREDERIC  T.  BIOLETTI 


With  the  great  expansion,  both  recent  and  prospective,  in  the 
volume  of  the  crop  of  shipping  grapes  in  California,  the  importance 
and  necessity  of  proper  standardization  becomes  increasingly  evident. 
There  is,  however,  much  difference  of  opinion  among  growers  and 
shippers  as  to  what  constitutes  proper  standardization.  Any  evidence, 
therefore,  which  may  throw  light  on  this  question  should  be  helpful 
in  arriving  at  a  satisfactory  solution. 

During  the  shipping  season  of  1918,  the  Division  of  Viticulture 
and  Fruit  Products  of  the  College  of  Agriculture  collected  data  with 
the  object  of  supplying  the  needed  evidence.  The  data  obtained  were 
not  sufficiently  extensive  to  settle  the  question  but  they  have  some 
value,  especially  in  the  light  of  the  experience  of  the  intervening 
seasons,  and  it  seems  advisable  to  publish  them  as  a  contribution  to 
our  knowledge  of  the  facts  and  as  a  basis  for  future  investigation. 

THE    OBJECT    OF    STANDARDIZATION 

The  object  of  the  establishment  of  a  legal  standard  of  saleability 
for  grapes  has  to  do  with  the  protection  of  both  the  grower  and  the 
consumer.  If  the  consumer  is  not  satisfied,  the  grower  must  event- 
ually go  out  of  business.  If  the  grower  does  not  realize  a  satisfactory 
return,  the  consumer  will  soon  be  unable  to  obtain  grapes.  The 
interests  of  the  two  are  therefore  interdependent. 

Whichever  viewpoint  is  taken,  therefore,  if  the  subject  is  con- 
sidered in  all  its  parts,  the  conclusion  must  be  the  same.  This 
conclusion  will  be  a  compromise  between  two  impossible  extremes — 
between  the  high  price  desired  by  the  grower  for  all  of  his  grapes 
and  the  high  quality  at  a  low  price  desired  by  the  consumer. 


Z  UNIVERSITY   OF    CALIFORNIA — EXPERIMENT    STATION 

The  standard  deals  directly,  of  course,  only  with  the  quality,  but 
its  value  to  the  grower  consists  in  its  effect  on  the  price  and  on  the 
quantity  of  grapes  sold.  If  it  is  set  too  high,  grapes  will  be  excluded 
from  the  market  for  which  the  consumer  would  be  willing  to  pay 
prices  profitable  to  the  grower.  If  it  is  set  too  low,  grapes  that  disgust 
the  purchaser  may  be  sold  at  a  profitable  price,  in  small  quantities 
and  for  a  short  time.  At  either  extreme,  the  market  is  limited  and 
the  value  of  the  industry  considered  as  a  whole  and  as  a  permanent 
resource  of  the  state  decreased.  If  the  question  is  judged  by  narrow 
local  interests  or  short-sighted  views  of  immediate  profits,  the  decision 
will  be  unwise. 

It  should  be  considered  rather  on  the  basis  of  the  effects  of  the 
standard  or  standards  proposed  on  an  important  industry  of  the 
state,  and  with  respect  to  the  future  in  so  far  as  this  may  be  possible. 


THE    NATURE    OF    STANDARDIZATION 

A  legal  standard  of  quality  is  quite  different  from  the  standard 
or  ideal  which  the  producer  of  grapes  must  keep  in  mind  if  he  is  to 
obtain  the  full  value  of  his  operations.  The  ideal  is  a  maximum  or 
optimum  standard  which  the  grower  can  approach  though  seldom 
reach.  The  legal  standard,  on  the  other  hand,  is  a  minimum  standard 
which  the  producer  must  reach  under  pain  of  disgusting  the  buyer 
of  his  grapes  and  suffering  from  the  latter 's  resentment  as  shown  by 
a  decrease  of  future  purchases. 

The  quality  of  a  grape  includes  many  factors,  which  are  of  two 
kinds :  those  which  are  evident  on  cursory  inspection,  and  those  which 
are  revealed  only  by  careful  examination  or  by  consumption.  The 
first  might  be  left  to  the  purchaser,  who  is  not  likely  to  buy  grapes 
which  appear  unattractive  or  inedible,  if  it  were  not  for  the  various 
devices  of  arrangement  and  packing  by  which  defects  can  be  con- 
cealed. 

The  principal  factors  are  (a)  those  which  appeal  to  the  eye,  e.g. 
color,  size,  and  form;  (&)  those  which  appeal  to  the  palate,  e.g. 
sweetness,  acidity,  flavor  and  texture;  and  (c)  those  which  concern 
the  " soundness"  or  condition  of  the  fruit  in  regard  to  mold,  decay, 
fermentation  and  mechanical  injuries. 

Most  or  all  of  the  factors  under  (a)  and  (c)  can  be  evaluated  by 
the  eye  of  the  trained  and  experienced  inspector.  Those  (&)  which 
depend  on  the  reactions  of  the  palate,  however,  offer  much  difficulty 
and  are  among  the  most  important.     They  are  included  under  the 


CIRC.  293]  THE  BASIS  OF  GRAPE  STANDARDIZATION  3 

term  maturity  or  ripeness.  When  a  grape  has  reached  the  stage  of 
its  development  at  which  it  can  be  eaten  with  satisfaction,  it  is  said 
to  be  ripe-,  when  it  has  reached  the  stage  at  which  it  gives  the  most 
satisfaction,  it  is  said  to  be  perfectly  ripe.  When  it  passes  this  stage, 
it  gradually  deteriorates  and  becomes  over-ripe. 

It  is  generally  conceded  that  the  legal  or  minimum  standard  should 
be  set  at  the  point  which  corresponds  with  the  first  of  these  stages, 
i.e  the  ripe  stage. 

It  is  here  that  the  greatest  difficulty  arises.  As  in  all  matters  of 
taste,  individuals  differ.  One  may  prefer  an  extremely  sweet  grape; 
another  a  degree  of  acidity  that  is  disagreeable  to  the  first.  The  taste 
of  the  same  individual,  moreover,  differs  with  different  conditions  of 
health  or  of  appetite.  A  minimum  standard,  therefore,  must  be  fixed 
at  a  point  that  will  satisfy  most  of  the  possible  purchasers  in  their 
usual  or  normal  condition. 

In  order  to  determine  this  point,  there  is  no  certain  method  but 
one  which  will  discover  the  average  taste  of  the  consumer.  When 
the  proper  standard  of  minimum  ripeness  is  determined  in  this 
way,  the  problem  of  enforcement  and  of  the  detection  of  failures  to 
reach  the  standard  must  be  solved.  The  various  and  variable  tastes  of 
inspectors  cannot  be  relied  upon.  There  is  needed  therefore  some 
character  which  can  be  measured  exactly  and  which  is  unaffected  by 
the  idiosyncrasies  and  the  physiological  or  psychological  condition 
of  the  inspector. 

Observation  has  shown  that  the  various  factors  characteristic  of 
ripeness  are  closely  correlated.  As  the  sweetness  increases,  so  does 
the  flavor  and  the  agreeability  of  the  color  and  texture,  while  the 
acidity  decreases.  A  measure  of  one,  therefore,  is  to  some  extent 
a  measure  of  the  others.  In  fact,  sweetness  and  ripeness  are  often 
spoken  of  as  though  they  were  identical.  Within  certain  limits  but 
with  important  exceptions,  this  is  nearly  correct. 

Sweetness  is  a  taste  and  cannot  be  measured  exactly.  It  is  usually 
assumed  that  the  amount  of  sugar  in  the  grape  is  a  measure  of  its 
sweetness.  As  the  amount  of  sugar  present  can  be  easily  and  rapidly 
determined  with  sufficient  accuracy  for  the  purpose,  if  the  assumption 
were  correct,  the  difficulty  would  be  much  decreased.  It  is  not,  how- 
ever, strictly  correct. 

Sweetness  is  an  effect  upon  the  organs  of  taste  and  depends  upon 
the  ratio  of  sugar  to  acid  as  well  as  upon  the  amount  of  sugar  present. 

The  ratio  of  sugar  to  acid  has  been  proposed  as  a  measure  of 
ripeness.    The  defect  of  this  measure  for  grapes  is  that  a  grape  with 


4  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

little  sugar  and  little  acid  may  have  the  same  "sugar: acid"  ratio  as 
a  grape  with  high  sugar  and  high  acid.  In  the  first  case,  the  grape 
may  be  undernourished,  defective  in  texture  and  totally  lacking  in 
pleasing  flavor  and  quality,  while,  in  the  second  case,  it  may  be 
perfectly  ripe  and  of  high  quality.  With  grapes  of  equal  sugar  per- 
centages, the  sugar  :acid  ratio  might  be  an  excellent  measure  of  rela- 
tive quality. 

INVESTIGATION    OF    1918 

With  the  object  of  discovering  how  far  the  sugar  content  could 
be  relied  upon  to  determine  quality  and  what  advantage  there  would 
be  in  the  substitution  or  addition  of  the  acid  test  or  of  the  sugar  :acid 
ratio,  the  data  to  be  considered  were  collected  in  1918. 

The  Grape  Standardization  Law  of  California. — In  1915,  the 
legislature  of  California  enacted  a  law  for  the  standardization  of 
fruit  packing,  which  included  grapes  for  table  use.  This  law  was 
amended  and  expanded  in  1917  and  1919  and  again  in  1921.  .  The 
provision  of  the  act  of  1921  regarding  maturity  or  sugar  content  is 
that  all  table  grapes  for  shipping  must  contain  at  least  17°  Balling, 
except  in  the  case  of  the  varieties  Emperor,  Cornichon,  Gros  Colman, 
Burger,  Pierce,  and  Isabella,  which  may  be  shipped  at  16°  Balling. 
This  includes  all  grapes  shipped  except  those  intended  for  manu- 
facturing purposes  and  special  grades  such  as  "California  Fancy 
Emperor"  packed  in  sawdust,  for  which  special  requirements  are 
made. 

Collection  of  Data. — The  guiding  principle  of  the  investigation 
was  to  compare  the  judgments  of  the  consumers  with  the  readings 
of  the  Balling  saccharometer  and  from  the  data  thus  obtained  to  try 
to  discover  how  far  they  agreed  and  whether  the  17°  Balling  or  16° 
Balling  standard  was  suited  to  attain  the  objects  of  the  law  or 
whether  it  should  be  changed  for  all  grapes  or  for  grapes  of  some 
varieties  or  for  some  localities. 

The  data  collected  covered  369  samples  from  77  packing  houses 
and  7  markets  in  several  localities  extending  from  the  Imperial  Valley 
through  the  San  Joaquin  and  Sacramento  valleys  to  Lodi.  The 
varieties  tested  were : 

Samples  Samples 

Malaga    120  Black  Prince  22 

Tokay    99  Cornichon   13 

Sultanina    43  Muscat    10 

Emperor    42  Miscellaneous  (11  var.)  ..       20 


CIRC.  293]  THE  BASIS  OP  GRAPE  STANDARDIZATION  5 

The  method  of  collecting  the  data  was  to  form  a  tasting  jury  of 
any  volunteers  who  could  be  found  in  the  packing  house  and  then  to 
obtain  their  judgments  on  samples  of  grapes  which  were  in  the  pack- 
ing house  ready  for  packing  or  already  packed.  From  three  to  six 
persons,  including  J.  R.  Zion,  Assistant  in  Viticulture,  who  collected 
the  data,  constituted  the  jury.  Each  member  of  the  jury  was  in- 
structed to  place  each  sample  of  grapes  in  one  of  the  following  classes, 
each  of  which  was  given  a  numerical  value. 

Class  Value                                  Class    ,  Value 

1.  Excellent    +  30  4.  Poor  0 

2.  Very  good   +  20  5.  Bad   — 10 

3.  Good    +  10 

The  final  classification  of  the  sample  was  made  by  adding  the 
numbers  assigned  by  each  taster  and  dividing  the  sum  by  the  number 
of  tasters.    This  gave  the  average  judgment  of  the  jury. 

The  sample  was  then  tested  for  its  Balling  degree  with  an  hydro- 
meter and  the  acidity  determined  volumetrically  as  tartaric  acid. 

The  data  for  all  the  samples  of  the  principal  varieties  which  had 
15.5°  Balling  or  over  are  shown  graphically  in  figure  1.  This  chart 
shows  some  of  the  limitations  of  the  method  and  also  the  need  of  more 
records  before  final  conclusions  should  be  drawn.  It  shows,  however, 
some  interesting  facts  and  tendencies. 

Influence  of  Locality. — It  has  been  contended  that  a  standard  of 
sugar  suitable  for  one  locality  might  be  unjust  to  another.  There  is 
some  apparent  justification  for  this  contention  in  the  records  for 
Malaga  in  the  Imperial  and  in  the  San  Joaquin  valleys.  Every 
sample  above  17.5°  Balling  from  Imperial  was  classed  as  good  or 
better,  while  nearly  20  per  cent  of  those  of  the  same  sugar  content 
from  the  San  Joaquin  Valley  were  classed  as  bad,  and  over  30  per 
cent  as  poor.  It  should  be  noted,  however,  that  all  the  samples  of 
17°  Balling  at  Imperial  were  classed  as  bad  and  that  over  10  per  cent 
of  the  same  degree  of  sugar  in  the  San  Joaquin  Valley  were  con- 
sidered good. 

One  reason  for  this  discrepancy  is  plain.  There  were  22  samples 
of  17°  grapes  tested  from  the  San  Joaquin  Valley  so  that  we  probably 
have  a  fair  average  there,  while  from  Imperial  there  were  only  2 
samples — much  too  few  for  a  reliable  judgment.  This  explanation 
is  less  plausible  for  the  discrepancy  between  the  5  Imperial  samples 
showing  19°  Balling,  which  are  all  "good,"  and  the  4  San  Joaquin 
samples  of  the  same  Balling  degree  which  are  50  per  cent  poor.  The 
cause  in  this  case  may  be  the  more  lenient  judgment  of  the  first  grapes 
of  the  season  before  the  palate  becomes  jaded  or  too  critical. 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


CIRC.  293]  THE  BASIS  OF  GRAPE  STANDARDIZATION  7 

Influence  of  Variety. — If  we  compare  the  Malaga,  Tokay,  and 
Emperor,  all  of  which  are  represented  by  a  fair  number  of  samples, 
we  shall  find  that  the  Balling  degree  at  which  all  samples  were  con- 
sidered good  was  20°  for  the  Emperor,  21°  for  the  Malaga  and  22° 
for  the  Tokay.  It  is  impossible  to  determine  whether  these  differences 
are  due  to  the  nature  of  the  varieties  either  in  part  or  in  whole.  It  is 
possible,  indeed  probable,  that  the  Tokay,  coming  in  mid-season  when 
the  market  is  well  supplied,  encounters  a  more  critical  consumer.  The 
Emperor,  coming  after  most  grapes  have  become  rare  on  the  market, 
is  judged  more  leniently. 

Influence  of  Number  of  Samples. — The  necessity  of  a  large  number 
of  samples  to  give  a  true  measure  of  the  consumer's  taste  is  shown 
very  clearly.  If  we  consider  only  the  three  varieties,  Malaga,  Tokay, 
and  Emperor,  which  are  represented  by  numerous  samples,  change  of 
opinion  as  the  sugar  increases  is  very  regular.  A  line  drawn  along 
the  tops  of  the  percentages  representing  bad  samples  or  poor  samples 
from  16°  Balling  up  is  a  very  smooth  curve  except  on  the  Emperor 
where  the  curve  is  regular  only  from  18°  Balling  up,  because  the 
lower  degrees  are  represented  by  only  one  sample  each  (see  fig.  1). 

Acid,  and  Balling: Acid  Ratios. — When  we  taste  a  grape,  its  appar- 
ent maturity  or  quality  as  shown  by  its  sweetness  is  not  due  to  the 
sugar  alone  but,  in  part,  to  the  ratio  between  sugar  and  acid  and, 
as  already  pointed  out,  this  ratio  has  been  proposed  as  a  basis  of 
standardization.  Another  basis  that  might  be  used  is  the  acidity 
alone  because  as  the  grape  ripens  the  acidity  diminishes. 

Figure  2  has  been  prepared  from  the  data  of  the  Malaga  samples 
as  a  means  of  comparing  the  relative  values  of  the  three  bases  of 
standardization.  The  last  graph — Balling  degree  and  quality — shows 
the  position  of  the  individual  samples  from  the  San  Joaquin  Valley 
by  black  dots  and  that  of  groups  of  variants  by  small  circles.  The 
large  circles  show  the  position  of  the  individual  samples  from  Im- 
perial. The  other  graphs  show  the  position  of  the  individual  samples 
from  Imperial,  but  the  position  only  of  the  groups  from  the  San 
Joaquin. 

A  comparison  of  the  three  standards  is  perhaps  best  made  by  con- 
sidering one  individual  sample.  The  sample  marked  by  A  and  a  large 
circle  was  No.  14  from  Imperial.  Its  composition  compared  with  the 
average  for  the  San  Joaquin  samples  of  the  same  Balling  degree  is 
shown  below. 

No.  14  from  Imperial  M<  an  from  San  Joaquin 

Balling  degree   16.40  16.40 

Acid    66  .99 

Balling: Acid   ratio    24.80  16.50 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


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CIRC.  293]  THE  BASIS  OF  GRAPE  STANDARDIZATION  9 

There  can  be  little  doubt  that  this  was  an  inferior  grape  although 
it  was  given  a  rating  of  +  6.6  by  the  jury  and,  therefore,  just  above 
the  +  5  line  which  limits  poor  quality.  A  grape  which  has  only 
two-thirds  of  the  normal  acidity  for  its  Balling  degree  is  a  poorly 
nourished  grape  which  will  never  develop  into  a  grape  of  high  quality 
however  long  it  remains  on  the  vine.  It  will  always  be  lacking  in 
the  flavor  which  distinguishes  a  good  eating  grape.  The  different 
positions  assigned  to  this  grape  by  the  three  standards  is  interesting. 
By  the  Balling  or  sugar  test  it  would  be  excluded  by  the  present 
standard  of  17°  Balling.  By  an  acid  test  which,  for  Malaga,  could 
hardly  be  placed  lower  than  .80  it  would  be  included  with  the  best. 
By  the  Balling  :acid  test  it  would  be  almost  exactly  on  the  border 
line  of  25  which  would  be  perhaps  a  reasonable  position  for  this 
standard. 

This  indicates  that  the  acid  test  is  quite  unreliable  and  that  the 
ratio  test  is  less  suitable  than  the  Balling  test  alone. 

Minimum  Standard  Indicated. — Whether  we  consider  varieties  or 
localities  or  season,  however,  the  evidence  indicates  that  in  no  case 
is  17°  Balling  sufficiently  high.  (See  figs.  2  and  3.)  There  is  also 
no  evidence  to  justify  the  special  standard  of  16°  Balling  for 
Emperor — only  two,  or  less  than  5  per  cent,  of  the  samples  tested  fell 
below  18°  and  these  two  samples  were  classed  as  bad  or  poor. 

If  we  take  these  data  at  their  face  value,  the  decision  must  be  that 
suitable  minimum  standards  are  for  Emperor  18°,  for  Malaga  19°, 
for  Sultanina  20°,  and  for  Tokay  21°  (fig.  1).  That  some  of  the 
samples  even  at  these  percentages  were  classed  as  poor  or  even  bad  is 
not  an  insuperable  objection  for  reasons  already  pointed  out,  and  also 
because  of  various  tastes  and  degrees  of  competence  of  the  jurors 
and  because  some  of  the  samples  classified  as  bad  were  probably  in 
bad  condition  and  would  have  been  rejected  on  this  score.  All  that 
we  can  expect  to  do  is  to  insure  that  the  grapes  which  reach  the 
market  will  please  a  large  majority  of  the  consumers  who  buy  them. 

A  better  way  of  using  these  data  for  the  determination  of  a  suit- 
able standard  is  shown  in  figure  3  and  the  bottom  graph  of  figure  2. 
In  these  figures,  the  black  dots  show  the  position  of  each  sample 
regarding  the  Balling  degree  and  the  taste  of  the  jury.  The  diagonal 
line  is  a  smooth  curve  drawn  from  the  small  circles  which  represent 
the  average  of  the  variants  differing  by  1°  Balling.  If  we  assume 
that  the  point  where  this  line  passes  through  the  horizontal  line, 
(+5),  dividing  the  " poor  "  from  the  "good"  represents  the  minimum 
quality,  we  obtain  for  the  four  varieties  the  following  standards — 


10 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


SUGAR    and  QUALITY 


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EXCELLENT 

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♦50 

VERYGOOD 

♦15 

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lyr 

POOR 

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6                 \ 

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TOKAY 

EXCELLENT 

45 

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VERYGOOD 

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Fig.  3 


Circ.  293] 


THE  BASIS  OF  GRAPE  STANDARDIZATION 


11 


Malaga  18.2°,  Emperor  18.5°,  Sultanina  19°,  and  Tokay  20.5°,  which 
is  from  .5°  higher  to  1°  lower  than  the  estimates  made  from  figure  1. 
It  is  more  reliable  because  the  smoothing  of  the  curves  allows  for 
unavoidable  mistakes  of  judgment. 

The  best  standard  is  that  which  includes  the  fewest  poor  grapes 
and  excludes  the  fewest  good  grapes.  If  we  accept  the  +  5  horizontal 
line  as  the  division  between  the  grapes  that  should  be  excluded  and 
those  which  should  be  included,  the  best  standard  will  be  represented 
by  the  vertical  line  which  excludes  the  fewest  samples  above  the  +  5 
line  and  includes  the  fewest  below  this  line. 

An  examination  of  the  graphs  of  figure  3  and  the  lowest  graph 
of  figure  2  makes  it  possible  to  estimate  the  efficiency  of  different 
standards  in  excluding  bad  grapes  and  including  good  ones.  The 
results  are  shown  in  the  following  table : 


TABLE  1 

Inclusion 

of  Bad  and 

Poor  Samples  and 

Exclusion  of 

Good 

with  Vakious  Balling  Degree  Standards 

Malaga 

Standard 

Inferior 

samples  included, 

bad                    poor 

Good 

samples  excluded 

Misplaced 
samples, 
total  per  cent 

(120  samples) 

17.0°  B. 

12                    16 

1 

29  =  24.0 

18.0 

0                     8 

1 

9=    7.5 

18.5 

0                     5 

3 

8=    6.7 

19.0 

0                     3 

9 

12  =  10.0 

Sultanina 

(43  samples) 

17.0°  B. 

7                     0 

2 

9  =  21.0 

18.0 

3                     0 

2 

5  =  11.7 

19.0 

0                     0 

5 

5  =  11.7 

Emperor 

(42  samples) 

16.0°  B. 

2                     2 

0 

4=    9.5 

17.0 

1                      2 

0 

3=    7.1 

18.0 

1                      2 

1 

4=    9.5 

19.0 

0                     1 

8 

9  =  21.4 

Tokay 

(99  samples) 

17.0 

14                    28 

0 

42  =  42.5 

18.0 

8                   27 

0 

35  =  35.4 

19.0 

5                   15 

3 

23  =  23.2 

20.0 

1                     5 

4 

10  =  10.1 

21.0 

0                     0 

7 

7=    7.1 

Table  1  indicates  that  the  best  segregation  of  the  bad  and  the 
good  grapes  would  be  by  a  standard  of  17°  Balling  for  the  Emperor, 
of  18°  Balling  for  the  Malaga  and  Sultanina  and  of  20°  Balling  for 
the  Tokay. 


12  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

We  are  thus  led  to  three  slightly  varying  results  by  considering 
the  data  in  three  different  ways  (a)  by  inspection  of  the  relative 
number  of  samples  at  different  qualities  at  different  Balling  degrees 
(figure  1)  ;  (&)  by  noting  at  what  Balling  degree  the  correlation  curve 
crosses  the  line  between  "poor"  and  "good"  quality  (figs.  2  and  3)  ; 
and  (c)  by  noting  what  Balling  degree  gives  the  best  separation  of  the 
good  and  bad  samples  (fig.  3  and  bottom  graph  fig.  2).  By  taking 
the  average  of  these  three  groups  of  results,  we  probably  come  as  near 
the  true  state  of  affairs  as  is  possible  with  the  incomplete  data  on 
which  they  are  based.     This  average  is  shown  in  the  following  table. 

TABLE  2 

Indicated  Mintmum  Standard 

Variety  (a)  (&)  (c)                                 Means 

Emperor    18  18.5  17  17.8  say  18.0 

Malaga    19  18.2  18  18.4  say  18.5 

Sultanina  20  19.0  18  19.0  say  19.0 

Tokay    21  20.5  20  20.5  say  20.5 


DISCUSSION 

The  value  of  the  results  of  this  investigation  depends  upon  the 
accuracy  of  the  tests,  the  competence  of  the  juries  and  the  extent  of 
the  field  covered. 

The  accuracy  of  the  tests  may  be  considered  sufficient,  as  it  is  at 
least  equal  to  that  which  could  be  obtained  in  the  application  of  any 
fruit  standardization  law.  The  extent  of  the  field,  however,  is 
insufficient.  It  should  cover  more  varieties,  more  localities  and  more 
samples  before  it  can  provide  a  reliable  basis  for  a  choice  of  standards. 

The  complete  competence  of  the  jurors,  moreover,  may  be  ques- 
tioned. The  graphs  indicate  that  they  attempted  to  be  fair  but  that 
perhaps  some,  at  least,  were  influenced  by  a  subconscious  bias.  If 
we  compare  the  classification  of  the  Tokay  samples  with  that  of  the 
Sultanina,  Emperor,  and  Malaga,  is  seems  highly  probable  that  some 
factor  entered  into  the  judgments  in  one  case  that  was  absent  in  the 
others.  Of  the  Tokay  samples,  the  jurors  classed  as  bad  or  poor  48 
per  cent  of  those  over  17°  Balling,  42  per  cent  of  those  over  18°  Ball- 
ing, 29  per  cent  of  those  over  19°  Balling,  and  12  per  cent  of  those 
over  20°  Balling.  Yet,  every  sample  of  Sultanina  over  19°  Balling 
except  one,  was  classed  as  good,  or  better,  and  only  3  per  cent  of 
Emperor  and  7.5  per  cent  of  Malaga  samples  showing  19°  Balling  or 
over  were  classed  as  poor.    It  seems  that  some  factor  other  than  those 


Circ.  293] 


THE  BASIS  OF  GRAPE  STANDARDIZATION 


13 


of  sweetness  and  flavor  must  have  influenced  the  tasters  of  Tokay. 
That  this  may  have  been  color  seems  to  be  indicated  by  the  following 
table  showing  the  average  judgment  of  samples  of  light  color,  of  fair 
color  and  of  good  color  at  each  Balling  degree. 


TABLE  3 
Balling,  Color  and  Quality  in  Tokay  Samples 

Fair  color 


Balling 

Light  color 

17 

—  7.5   (  8)* 

18 

—  1.0   (13) 

19 

—  1.0   (15) 

20 

0.0   (  7) 

21 

+  7.9   (  6) 

22 

+  7.5   (  1) 

23 

—  1.3 

—  0.3 

—  2.5 
+  6.0 


(2) 
(3) 
(1) 
(1) 


Good  color 

—  1.0   (  2) 

+  4.6   (  4) 

+  5.5   (  5) 

+  6.9   (18) 

+  10.3   (10) 

+  15.0   (  2) 

*  The  figures  in  parentheses  are  the  number  of  samples ;  the  other  figures,  the 
ratings  as  explained  on  page  5. 

The  table  indicates  that  the  judgment  of  the  tasters  was  influenced 
by  color  to  some  extent.  There  is  little  difference  after  21°  Balling 
is  reached,  or  below  19°  Balling,  but  at  19°  and  20°  Balling  the 
well  colored  samples  are  rated  considerably  higher  than  the  light 
colored. 

It  seems  then  from  this  preliminary  inquiry  that  a  single  invari- 
able standard  has  serious  defects  and  that  a  perfect  standardization 
law  might  have  to  adopt  standards  which  varied  with  variety  and 
season,  and  perhaps  with  locality  or  even  color.  The  following  table 
based  on  the  data  shown  in  figure  1  shows  the  evidence  on  some  of 
these  points. 

Influence  of  Variety,  Locality  and  Season  on  the  Correlation  of 


Balling  Degree  and  Q 

UALITY 

(See 

fig. 

1) 

The  figures  represent  percentage 

S 

17° 

18° 

19° 

20° 

21° 

A 

22° 

A 

Variety 

B 

P 

G 

B        P 

G 

B 

P 

G 

B 

P 

G 

B 

P 

G     B 

P 

'  G 

Malaga 

51 

35 

14 

22      30 

48 

0 

50 

50 

0 

34 

66 

100      .... 

100 

Tokay 

100 

45      55 

16 

58 

26 

8 

54 

38 

6 

14 

80      .... 

100 

Emperor* 

50 

50 

16      18 

66 

15 

85 

100 

100      .... 

100 

Localities 

Imperial* 

75 

25 

100 

100 

.... 

100 

100      .... 

100 

San   Joaquin 

50 

43 

7 

19      24 

57 

33 

67 

0 

17 

83 

0 

0 

100      .... 

100 

Lodi 

100 

45      55 

16 

58 

26 

8 

54 

38 

6 

14 

80      .... 

100 

Season 

Early 

75 

25 

100 

100 

.... 

100 

.... 

100      .... 

100 

Midseason 

75 

18 

7 

34      42 

24 

8 

54 

38 

4 

44 

52 

3 

7 

90      .... 

100 

Late 

50 

50 

16      18 

66 

.... 

15 

85 



100 

100      .... 

100 

B  =  bad;  P 

=  P< 

>or ; 

G  = 

good  or  better; 

B  - 

f  P 

-|-G  = 

100. 

=  16°   and  17°  balling  included. 


14  UNIVERSITY   OF    CALIFORNIA — EXPERIMENT    STATION 

We  may  assume  that  when  80  per  cent  of  the  jury  consider  the 
sample  good  or  better  that  there  is  no  doubt  of  its  being  of  sufficiently 
high  quality  to  please  the  average  consumer.  With  this  assumption  it 
appears  that  the  Emperor  was  good  when  it  reached  19°  Balling, 
and  the  Malaga  and  Tokay  when  they  reached  21°  Balling.  The 
grapes  from  Imperial  were  good  at  18°,  those  from  the  Upper  San 
Joaquin  at  20°  Balling,  and  those  from  Lodi  at  21°  Balling.  Early 
grapes  were  found  satisfactory  when  they  reached  18°,  late  grapes 
when  they  reached  19°  Balling,  and  mid-season  grapes  when  they 
reached  21°  Balling. 

It  is  probable  that  variety,  locality  and  season  each  has  its  effect 
in  modifying  the  taste  of  the  consumer,  but  how  much  influence  each 
exerts  the  data  are  too  meagre  to  determine  exactly. 

The  variety  may  influence  the  taste  of  the  consumer  directly  by 
the  combination  of  flavor,  sugar  and  acidity,  and  texture,  or  indirectly 
by  the  psychological  influence  of  color,  size  or  other  visual  effect. 
The  locality  may  influence  any  of  the  factors  which  determine  the 
judgment  of  the  consumer.  The  Balling  :acid  ratio  may  vary  for  the 
same  variety  in  different  localities  owing  to  the  influence  of  climate 
and  soil,  and  the  same  is  true  of  color,  size  and  flavor.  The  season 
may  change  the  judgment  by  making  the  taster  more  or  less  critical 
according  to  the  rarity  or  abundance  of  grapes.  When  the  earliest 
grapes  reach  the  market,  the  consumer  has  not  eaten  grapes  for  many 
months  and,  when  the  latest  arrive,  grapes  have  become  a  rarity.  In 
mid-season,  there  is  much  competition  not  only  between  different  lots 
of  grapes  but  with  other  fruits,  and  the  taste  for  grapes  has  been  more 
or  less  satiated. 


CIRC.  293]  THE  BASIS  OF  GRAPE  STANDARDIZATION  15 


CONCLUSIONS 

The  only  conclusions  that  it  seems  safe  to  draw  from  this  study 
are: 

1.  That  the  Balling  degree  test  is  the  simplest  and  most  reliable 
that  can  be  used  practically  in  determining  the  degree  of  ripeness  of 
grapes  for  the  purposes  of  the  standardization  of  shipping  grapes. 

2.  That  the  standardization  law  of  1921  probably  requires  modi- 
fications of  its  provisions  regarding  the  Balling  degrees  required  for 
shipping  grapes. 

3.  That  these  modifications  should  probably  include  adjustments 
of  the  required  Balling  degree  to  suit  the  varying  conditions  of 
variety  and  season.  The  need  of  an  adjustment  for  variations  of 
locality  is  doubtful,  and,  in  any  case,  would  be  very  difficult  of 
enforcement. 

4.  That  more  information  is  needed  before  the  proper  modifica- 
tions of  the  law  can  be  made. 

5.  That  the  method  used  in  this  investigation  if  sufficiently 
expanded  and  improved  in  detail  in  the  light  of  the  experiences 
obtained  is  a  good,  perhaps  the  best,  method  of  quickly  reaching  a 
wise  decision  in  this  matter. 


0> 


